Re: [PATCH net v3 3/5] can: rockchip_canfd: cancel bus-off restart before closing the device

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] pm: async pm_runtime_put() before pm_runtime_disable() leaves hardware active
--

commit 614c95a9bb5ead8b95b8b6a430415575bc664f43
Author: Cunhao Lu <1579567540@qq.com>

can: rockchip_canfd: cancel bus-off restart before closing the device

This commit fixes a race condition during device close by cancelling the
bus-off restart work early. It adds synchronous cancellation to ndo_stop()
while resources are still available, preventing late restarts. The patch
also improves interrupt handling and RX offload enablement.

> diff --git a/drivers/net/can/rockchip/rockchip_canfd-core.c b/drivers/net/can/rockchip/rockchip_canfd-core.c
> index 37c1c22c40c9f..4b3db07242395 100644
> --- a/drivers/net/can/rockchip/rockchip_canfd-core.c
> +++ b/drivers/net/can/rockchip/rockchip_canfd-core.c

[ ... ]

> @@ -758,6 +775,7 @@ static int rkcanfd_stop(struct net_device *ndev)
>  {
>  	struct rkcanfd_priv *priv = netdev_priv(ndev);
>  
> +	close_candev_cancel_restart_sync(ndev);
>  	netif_stop_queue(ndev);
>  
>  	rkcanfd_chip_interrupts_disable(priv);

[Severity: Medium]
Later in this function, pm_runtime_put(ndev->dev.parent) is called.

Since pm_runtime_put() queues an asynchronous idle request, it can leave the
hardware active.

When rmmod is executed, the removal path calls rkcanfd_remove() which calls
rkcanfd_unregister():

static inline void rkcanfd_unregister(struct rkcanfd_priv *priv)
{
	struct net_device *ndev	= priv->ndev;

	unregister_candev(ndev);
	pm_runtime_disable(ndev->dev.parent);
}

unregister_candev() synchronously brings the interface down by calling
rkcanfd_stop(), followed immediately by pm_runtime_disable() in
rkcanfd_unregister().

Because pm_runtime_disable() detects and cancels the pending async
idle/suspend work queued by pm_runtime_put() in rkcanfd_stop(), the device is
never suspended, leaving the hardware clocks enabled and powered on
indefinitely after the driver is removed.

Could this be a regression? Should pm_runtime_put_sync() be used in
rkcanfd_stop() instead of pm_runtime_put() to ensure the hardware is suspended
before pm_runtime_disable() cancels the work?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261014-rockchip-canfd-restart-close-v3-0-f0eb41090242@qq.com?part=3